What led to the decline of the Nationalist historian breed in India post 60's

After producing some great nationalist historians in the previous decades why did India see a paucity of nationalist historians upto the modern time. How did they cede space to the Marxist historians? Did it have anything to do with the lack of a need for a strong nationalistic narrative as India had already become free and confident as a nation by then. From the 60's to the late 90's (when the BJP came to power) was the nationalistic historian dark age. Slowly this has been reinvograted and now there is a possibility of a resurgence (although still much behind the Marxists). but during the time between the 60's and late 90's who were the major nationalist Historians/Indologists? How did their careers pan out in this very difficult time?

In the early 70's a hardcore leftist - Sayid Nurul Hasan, a very charismatic person from erstwhile Muslim aristocratic family of UP was made education minister of India. (I can't vouch the authenticity of information but I have read somewhere that Education ministry was demanded by Communist Party of India - Marxist (CPI-M) in return for their support to Indira Gandhi. It was under that power deal that Nurul Hasan was made Education minister). Far from being hardcore leftist, Sayid Nurul Hasan was also a historian himself and hence completely well suitable for the task. It was he who thoroughly raped the entire Indian academia (and education system of India, too IMO). First he created Indian council of historical research (ICHR) and gave it huge powers to fund and patronize the historian (in other words virtually control the strings for the academical research), which it still have and made RS Sharma (another hardcore Marxist) head of it, who just accentuated the entire process. Then he also put the person with same ideological leaning as the head of UGC (University grants commission), another institute with immense authority over Universities and their affairs) and also brought Indian Historical Congress under their controlled. With all these institutes with immense power under their control, it was just a matter of time before they purged the Delhi academia. (Aligarh Muslim university was probably always under their control). And after that they slowly started controlling regional academical centers like Vadodara, Allahabad, Kolkata, Calicut etc. Remember 70s was also the period of Indira's authoritarian regime and it just made their work easier. (For instance during emergency many eminent scholars from Sanskrit department of DU were thrown into jail and rather than protesting in their support, these Marxists were delighted, the same people who now present themselves as upholders of free speech and secularism). Communists of India belongs to the great tradition of liars (Consider every self confessed Indian communist a liar until proven otherwise). It is probably because of that, it took some time for the people to realize the raping of the Indian academia that was going on for all those times. It was thanks to heated issue of Ram temple that ultimately created "do or die" kind of situation for the entire RW and brought them into aggressive mode. Otherwise this shameless raping would have still been going on. (IMO this whole Ram temple issue didn't shake the secularism of India but rather exposed how rotten those ethos were to begin with).